Arabidopsis Histone Methyltransferase SET DOMAIN GROUP8 Mediates Induction of the Jasmonate/Ethylene Pathway Genes in Plant Defense Response to Necrotrophic Fungi
Arabidopsis Histone Methyltransferase SET DOMAIN GROUP8 Mediates Induction of the Jasmonate/Ethylene Pathway Genes in Plant Defense Response to Necrotrophic Fungi
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DOI：
10.1104/pp.110.161497
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发表时间：
2010-11-01
期刊：
影响因子：
7.4
通讯作者：
Shen, Wen-Hui
中科院分区：
文献类型：
--
作者：
Berr, Alexandre;McCallum, Emily J.;Shen, Wen-Hui
作为一种无根生物，植物必须忍受各种各样的生物和非生物胁迫，因此它们进化出了复杂的、可快速诱导的防御策略，这些策略与一系列基因的激活有关。在其他机制中，染色质结构的变化被认为为基因转录的调控提供了一种灵活、全局和稳定的手段。为了支持这一观点，我们在这里证明了拟南芥（Arabidopsis thaliana）组蛋白甲基转移酶SET DOMAIN GROUP8 （SDG8）通过调节茉莉酸（JA）和/或乙烯信号通路中的一组基因在植物防御真菌病原体中起着至关重要的作用。我们发现，丧失功能的突变体sdg8-1对坏死性真菌病原体油菜交替菌和灰霉病菌的抗性降低。虽然在sdg8-1中，参与植物防御的主要植物激素JA和抗真菌病原体的主要植物抗菌素camalexin的水平保持不变甚至高于正常水平，但在真菌感染或JA处理下，突变植物中JA/乙烯信号通路中几种防御基因的诱导严重受损。在sdg8-1中，下游基因以及上游有丝分裂原活化蛋白激酶基因MKK3和MKK5都被错误调控。因此，染色质免疫沉淀分析表明，sdg8-1破坏了防御标记基因以及MKK3和MKK5上组蛋白H3赖氨酸36甲基化的动态变化，这种变化通常发生在野生型植物感染真菌病原体或甲基JA处理后。我们的数据表明，sdg8介导的组蛋白H3赖氨酸36甲基化可能作为一种允许转录的记忆，用于一部分防御基因，允许快速建立转录诱导。
As sessile organisms, plants have to endure a wide variety of biotic and abiotic stresses, and accordingly they have evolved intricate and rapidly inducible defense strategies associated with the activation of a battery of genes. Among other mechanisms, changes in chromatin structure are thought to provide a flexible, global, and stable means for the regulation of gene transcription. In support of this idea, we demonstrate here that the Arabidopsis (Arabidopsis thaliana) histone methyltransferase SET DOMAIN GROUP8 (SDG8) plays a crucial role in plant defense against fungal pathogens by regulating a subset of genes within the jasmonic acid (JA) and/or ethylene signaling pathway. We show that the loss-of-function mutant sdg8-1 displays reduced resistance to the necrotrophic fungal pathogens Alternaria brassicicola and Botrytis cinerea. While levels of JA, a primary phytohormone involved in plant defense, and camalexin, a major phytoalexin against fungal pathogens, remain unchanged or even above normal in sdg8-1, induction of several defense genes within the JA/ethylene signaling pathway is severely compromised in response to fungal infection or JA treatment in mutant plants. Both downstream genes and, remarkably, also upstream mitogen-activated protein kinase kinase genes MKK3 and MKK5 are misregulated in sdg8-1. Accordingly, chromatin immunoprecipitation analysis shows that sdg8-1 impairs dynamic changes of histone H3 lysine 36 methylation at defense marker genes as well as at MKK3 and MKK5, which normally occurs upon infection with fungal pathogens or methyl JA treatment in wild-type plants. Our data indicate that SDG8-mediated histone H3 lysine 36 methylation may serve as a memory of permissive transcription for a subset of defense genes, allowing rapid establishment of transcriptional induction.